diff --git a/swh/storage/buffer.py b/swh/storage/buffer.py
--- a/swh/storage/buffer.py
+++ b/swh/storage/buffer.py
@@ -4,6 +4,7 @@
 # See top-level LICENSE file for more information
 
 from functools import partial
+import logging
 from typing import Dict, Iterable, List, Mapping, Sequence, Tuple
 
 from typing_extensions import Literal
@@ -21,6 +22,9 @@
 from swh.storage import get_storage
 from swh.storage.interface import StorageInterface
 
+logger = logging.getLogger(__name__)
+
+
 LObjectType = Literal[
     "content",
     "skipped_content",
@@ -191,6 +195,8 @@
     ) -> Dict[str, int]:
         summary: Dict[str, int] = {}
 
+        logger.debug("flushing %s", {k: len(self._objects[k]) for k in object_types})
+
         def update_summary(stats):
             for k, v in stats.items():
                 summary[k] = v + summary.get(k, 0)
@@ -208,7 +214,7 @@
         update_summary(stats)
 
         self.clear_buffers(object_types)
-
+        logger.info("flushed %s", summary)
         return summary
 
     def clear_buffers(self, object_types: Sequence[LObjectType] = OBJECT_TYPES) -> None: